1. Field of the Invention
The present invention relates to a zoom lens system capable of correcting a change of an image position due to vibrations.
2. Related Background Art
As disclosed in Japanese Patent Laid-Open Application No. 1-191113, there is a zoom lens having two or more lens groups in which a predetermined lens group is shifted in a direction perpendicular to an optical axis to correct a change of an image position due to movement of the hands, vibrations of the zoom lens system, etc. (hereinafter referred to as "vibration correction" or "image position correction").
However, in the above zoom lens, the diameters of lenses of the lens group to be shifted in the direction perpendicular to the optical axis for the image position correction, i.e., the diameters of lenses of the vibration correcting group, are large and the total thickness of the vibration correcting group in the optical axis direction is large. Therefore, a vibration correcting mechanism becomes large in size, so that it is difficult to make the lens barrel compact. Namely, in the conventional vibration correcting zoom lens, the whole photo-optical system becomes large, thereby causing inconveniences in terms of portability and operability.